During the floods of August, 1909, Shafts Nos. 2 and 3 were damaged beyond repair, and sand and gravel, entering through them, blocked up the gallery to within about 150 ft. of Shaft No. 1. The interior timbering probably collapsed, due to cavings and disturbance in the river-bed during the period of maximum flood, but no explorations have been possible on account of the great quantity of water still coming through (at present more than 650 liters per sec.). For this reason the work of driving the gallery, as well as lining Shaft No. 1, has been suspended. [Illustration: PLATE XXVIII, FIG. 2.--VIEW OF SANTA CATARINA RIVER IN FLOOD, ON AUGUST 28TH, 1909.] [Illustration: PLATE XXXI, FIG. 1.--FLUSH-TANK CARRIED DOWN BY FLOOD OF AUGUST 27TH-28TH, 1909.] [Illustration: PLATE XXXI, FIG. 2.--VIEW SHOWING SCOURING EFFECT OF FLOOD ON SAN GERONIMO AQUEDUCT.] [Illustration: PLATE XXXII, FIG. 1.--VIEW OF SANTA CATARINA RIVER AFTER THE FLOOD.] [Illustration: PLATE XXXII, FIG. 2.--VIEW OF SANTA CATARINA RIVER FLOWING THROUGH LOW-LYING STREETS, 8 DAYS AFTER THE FLOOD.] On reaching the city, the flood of August, 1909, swept away two streets adjoining the river. These streets had been built on made ground, in what was originally the river-bed. The sewers and water mains laid in them were destroyed entirely, and some 460 ft. of the 24-in. cast-iron pipe, buried under the river-bed at a depth of 8 ft., were carried away. In relaying this portion of the main, and for protecting the remainder of it across the river, it is now proposed to encase it in a solid rubble concrete block, 8 ft. square, which will impart weight and stability against the scouring effect of floods.